Liquid weighing apparatus



Oct. 13, 1942. H. RICHARDSON 2,298,967

LIQUID WEIGHING APPARATUS Filed July 27, 1938 12 Sheets-Sheet l ll llllgwucmm Oct. 13, 1942. H. RICHARDSON 2,293,957

LIQUID WEIGHING APPARATUS Fil ed July 27, 1938 12 Sheets- Sheet 2 H'.RICHARDSON LIQUID WEIGHING APPARATUS Filed July 27, 1958 12 Sheets-Sheet5 Oct. 13, 1942.

H. RICHARDSON LIQUID WEIGHING APPARATUS 12 Sheets-Sheet 6 Filed July 27,1938 Oct. 13, 1942. H. RICHARDSON LIQUID WEIGHING APPARATUS Filed July27, 1938 12 Sheets-Sheet '7 m W W 1942 H. RICHARDSON LIQUID WEIGHINGAPPARATUS Filed July 27, 1938 12 Sheets-Sheet 8 Oct. 13, 1942.

H. RICHARDSON 2,298,967 LIQUID WEIGHING APPARATUS File d July 27, 195812 Sheets-Sheet 10 1942 H. RICHARDSON 2,298,957

LIQUID WEIGHING APPARATUS Filed July 27, 1958 12 Sheets-Sheet ll mienyum S Oct. 13, 1942. 1

H. RICHARDSON LIQUID WEIGHING APPARATUS Filed July 27, 1958 12Sheets-Sheet 12 with temperature conditions. object of the presentinvention to avoid such the tank after discharge. with the tank,constitutes a tarewhich is carried Patented Oct. 13, 1942 UNITED STATESPATENT OFFICE LIQUID VVEIGHING APPARATUS Henry Richardson, Passaic, N.J., assignor to Richardson Scale Company, Clifton, N. J., a corporationof New Jersey Application July 27, 1938, Serial No. 221,617

16 Claims.

The present invention relates to apparatus for rapidly and accuratelyweighing or measuring liquids, and particularly'to a heavy duty machinefor auomatically weighing and registering large units of liquidwhile-maintaining a substantially continuous flow of the liquid from itssource through the machine and to a point of use or to storage.

In prior apparatusof this general type, embodying one or more tanksthrough which liq- Such errors, furthermore, obviously are variable t isthe primary charges units of liquid in such manner that they can notvary from a predetermined value.

This is accomplished by amultiple-beam scale-system so coordinated withthe control valves of a weigh tank that there is always a residue ofliquid in This residue, together in balance by a tare beam of the scalesystem; and a weigh beam is-provided and so related to the tare beamthat units of liquid are'weighed .into and out of the tank accurately.

It is another major object of the present invention to devise a scalesystem that is far greater in accuracy in the weighing of liquids thanany apparatus heretofore proposed for the purpose. Aside from theavoidance of error due to viscosity, the present scale system embodiesseveral arrangements for reducing errors to an absolute .minimum. .lnfact theapparatus of this invenalso an object to discharge the weighedliquid into a receiving tank or tanks while maintaining a substantiallyconstant head of liquid in the latter.

Another important object resides in the provision of valve means andoperating mechanism therefor which will handle a large volumetric flowof liquid and yet cut the flowing liquid accurately into weighed units.

A further object is to provide an overweight and underweight device forpreventing discharge of any unit of material which does not have apredetermined weight within the prescribed tolerance (permissible rangeof very slight inaccuracyplus or minus) of the weighing machine.

Preferably, in order to obtain a practically unbroken stream of liquidthrough the machine, two weigh tanks are provided and operated in timedrelationship but out of phasethat is, so that one tank discharges whilethe other is fed, and vice versa. 'It is amajor object of the presentinvention to devise a much improved system of this general characterand, in particular, to provide an electric interlocking arrangement forautomatically bringing the twin scale units into step or alternation andmaintaining them in such relationship.

The electric arrangement preferably includes a time delay relay forpermitting the scale to come to proper balance for each weighing priorto operation of the weigh tank control valves. It further includesvarious elements for preventing improper operation, and variousindicators and'signals, all of which will be described in detailsubsequently.

It is a highly important object of the-present invention to devise aquickly and easily adjustable valve, for use in a system of thecharacter described, having a dribble flow as well as full flow andcut-off positions of adjustment. In particular it is an object toprovide a pair of such valves, for feeding and discharging respectivelyin association with a weigh tank that must be balanced twice on amultiple-beam scale system as each unit of liquid passes through thetank. Still'more specifically, it is an object to provide,

1 a dual scale system, two sets of pairs of such valves in associationwith means for automatically moving the valves in properly timed relationship to their several positions so that a substantially unbrokenstream of liquid is divided accurately into measured or weighed units.

It is a further major object of this invention to device an apparatus,of the general character described, which is especially adapted tohandle volatile and inflammable liquids. In this connection, subordinateobjects reside in the provision of a completely closed pipe and tanksystem, with the flow into each tank of the system taking place at apoint of submersion; in the provision of fume seals for the actuatorswhich extend inwardly to the valves of the liquid handling system, andof interconnections between the upper ends of the tanks of the system,without normally venting the interconnected tanks to atmosphere; and inthe provision of electric motors that are explosion-proof, and varioussealed and explosion-proof electrical units in association with saidmotors.

The objects stated and expressed in the foregoing discussion, and otherand more specific objects as well, will clearly appear from thefollowing detailed description when studied in conjunction with theaccompanying drawings and the appended claims. In the drawings, whichillustrate a single embodiment that is preferred for handling a largevolumetric flow of volatile liquids such as gasoline, oils and the like:

Fig. 1 represents a front elevational view of the complete apparatus,with portions of certain parts broken away or sectioned for clarity ofillustration Fig. 2 1s a side elevation as seen when looking toward theleft-hand end of Fig. 1;

Fig. 3 is a top plan view of the apparatus of Figs. 1 and 2;

Fig. 4 is a rear elevational view, with the overflow tank detached;

Fig. 5 is a perspective and somewhat diagrammatic view designed toclarify the relationships of the major parts of one of the twin scaleunits;

Fig. 5A is a similar view designed to clarify the relationship of one ofthe multi-bearn systems to its corresponding weigh tank;

Figs. 6, '7 and 8 are detail views representing, respectively, a frontelevational view (rotated 90 degrees to the right), and plan and sideelevational showings of one of the scale motors and its associated valveoperating mechanism;

Figs. 9 and 10 are diagrammatic showings of one of the liquid controlvalves and its actuating means, in dribble flow and cut-off positionsrespectively;

Fig. 11 is an enlarged detail view, in vertical section, of one of thecontrol valves;

Fig. 12 is a detail view, in vertical section, of one of the fume sealdevices for permitting operation of the valves without escape of gases;

Figs. 13 and 14 are front and side elevational views respectively, eachin partial section, of a device responsive to variations in liquid leveland forming part of the apparatus of Figs. 1 to 4;

Figs. 15 to 18 are schematic illustrations of four effective positionsof a scale beam lift mechanism and the corresponding positions of a setof six switch-actuating cams that are synchronized with said liftmechanism;

Figs. 19 to 24 are schematic illustrations of six different positions ofone of the tare and weigh beam assemblies and the correspondingpositions of a plurality of switches and of said beam lifting mechanism;

Fig. 25 is an enlarged detail view, in perspective, of what willhereafter be referred to as an overunder device for ensuring that allmeasured units of liquid will have a weight within a prescribedtolerance;

Fig. 26 differs from Fig. 25 only in the removal of certain parts andthe spacing of others to obtain clarity of illustration;

Fig. 27 is a fragmentary detail view of a portion of the device of Fig.25;

Fig. 28 is a fragmentary section of one of the dash-pots of Figs. 25 and26;

Figs. 29 to 33 are diagrammatic illustrations of various positionsassumed by one of the overunder devices in response to movements of theassociated tare beam;

Fig. 34 is a wiring diagram including circuits and controls for bothsides of the illustrated dualscale system.

With continued reference to the drawings, wherein like characters areemployed to designate like parts, and with particular reference for themoment to Figs. 1 to 4, the framework, tanks and piping arrangements ofthe system will first be described. A framework 4iicomprising aplurality of intertied elements, ladders and platforms, asshown-supports a pair of receiving tanks 4|, a pair of weigh tanks 42and a pair of feed tanks 43, each pair superposed above the other in theorder named. For alternated weighings with twin scales it is essentialthat there be two tanks 42, but single large feed and receiving tankswould sufiice. The latter are formed in pairs only for convenience ofmanufacture, shipment and installation. There is also an overflow tank44, connected by a pipe 45 to one of the feed tanks in such manner thatan excessively high level of liquid can not be attained in the latter.

A pipe line 48 supplies, let us say, gasoline from a tanker to one ofthe feed tanks 43. In effect it supplies both tanks as they areconstantly interconnected through discharge branches 41 which feed intoa common discharge conduit 48. The tops of these tanks also areinterconnected, by a pipe 50, so that vapor pressures are equalized. Infact, the upper parts of the interiors of all seven tanks areinterconnected to have a common fume or vapor vent valve 5| which may beadjusted to open to atmosphere at any preselected abnormal pressure.This is accomplished by a vertical pipe 52 connected into the pipe 50,branch pipes 53 leading from tanks 4! to pipe 52, branch pipes 54leading from tanks 42 to pipe 52, a pipe section 55 between the valve 5|and one of the tanks 43, and a pipe 56 connected between the overflowtank 44 and the section 55. All tanks are closed to atmosphere exceptfor possible relief through valve 5!, and thus have their vapor spacesin intercommunication. Therefore, danger is eliminated, and losses byevaporation are minimized.

The pipe branches 5 contain flexible sections 5'! of oil-proof syntheticrubber or the like so as not to impose appreciable resistance to risingand falling movements of the weigh tanks 42 to which the pipe branches54 are rigidly connected. Each weigh tank is mounted on an individualscale system (later described) and hence must be free for suchmovements. All other tanks are rigidly mounted. Each weigh tank has asingle central connection 58 in its bottom through which both feedingand discharging takes place, alternately, depending upon the positionassumed by a feed valve 6!! disposed between each connection 58 and thefeed conduit 48 and upon the position of a discharge valve 61 disposedbetween each connection 58 and a pipe line 52 that is connected to therear end of each receiving tank 4|. In a manner explained later theoperation of the two pairs of valves, 65, 6|, is timed so that the feedvalve of one weigh tank is open while that of the other is closed, thesame being true of the respective discharge valves. And of course eachdischarge valve is closed whilev itsv associated feed valve is open, andvice versa (see Fig. l)

The connections 58 include tubular sections 63 that are formed ofoil-proof synthetic rubber and that are flexible vertically as well ascapable of slight longitudinal contraction and expansion. Hence theyimpose no appreciable resistance to vertical movement of the weightanks.

The pipe EZ connects to-the receiving tanks 4! adjacent the bottomsthereof, attd; and the liquid in these tanks may be periodically orcontinuously removed to waitingtank-cars or to a large remotestorage'tank (not shown) by ap-ipeline 65 which contains a dischargepump 65 driven by an electric motor DPM.

It should be observed that in each instance the seven closed-tanks arefed in submersionthat is, the point of fluid entry is adjacent the tankbottom and normally below the liquid level of the particular tank. Thisis done to reduce turbulence and vaporization to a minimum. Thisadvantage is augmented by placing bafile plates 6? in some of the tanks(see Fig. l It will also be observed that all valves are external forready accessibility and for avoiding the danger of sending men into thetanks for pur oses of inspection and repair.

The common level of liquid in the two feed tanks "53 is indicated by apointer 68 actuated by a float device 18. Constant head feed switchdevice CHF (Fig. 1) is connected to the top and bottom of one tank 33 bya conduit H and designed to keep a certain electrical circuit open (asexplained later in detail) so that the feed valves 6% can not admitfluid to the weigh tanks until a definite head of liquid is reached orexceeded in the feed tanks. This provision increases the accuracy of theweighings. In like manner and likewise for accuracy a constant headdischarge device CH1) is connected into one of the receiving tanks 4|by-a conduit 72 so that a weighed unit of liquid normally cannot bedischarged into either tank unless a substantially constant head exists,with-the level so-predetermined that there is room for the weighed unitin these tanks. A suitable control device of this character is shown inFigs. 13 and 14, described later.

The overflow tank 4-4 is connected at itsbottom by a pipe :3 to a pump.4 which can be utilized to return the liquid to the feed tanks by wayof a pipe 75 (Fig. 1). This overflow pump is driven by an electric motorPM which is so related. (as explained in detail later on Fig. 34)

With reference now in particular to Fig. 5

the control valves 63 and SI of each scale system depend primarily fortheir actuation upon a pair of cams 8B and 8| respectively and upon apair of solenoid units FS and DS electric scale motor SM operatesthrough a reducing gear unit 82 to drive a shaft 83 upon which the camsare secured. Below each cam there is disposed a roller 454 carried by alever 85 that is pivoted at one end at 85 upon the respectively. An

or partially open in .-drib e u" cooperate with the levers framework, asindicated. Between each roller and pivot the lever is pivotallyconnected to a vertical link 81, the latter in turn being pivotallyconnected to one end of a small walking beam 88 that is pivoted on theframework between its ends, as shown. The other end of each walking beamis pivotally connected to an elongated valve rod 90 which projectsdownwardly through a sleeve 9| into connection with a feed valve 68 or adischarge valve 5|, as the case may be (see also Fig. 1).

In the case of the feed valve the last named connection is made directto the shiftable valve unit 92 (Figs. 1 and 11) through a valve stem butfor the dischar e valvewhich unseats downwardly instead of upwardlytheconnection is indirect and comprises a small walking beam 2 3 pivotedbetween its ends on a housing within which it is disposed. The oppositeends of the beam 34 are pivotally joined to the corresponding rod es andstem 93, so that downward movement of the rod will cause closure ofthevalve. All control valves, therefore, are closed by the weight of therods st augmented by the pressure of the liquid tending to escapethrough the valves. Upward movement of the rods iifi to open the valvesmust be positive and is brought about periodically (in a certain timedrelation as subsequently seen) by forceful engagement of enlargedportions 95 of the cams 33 with the rollers 3Q (Figs. 5, 9 and 10).

The two sleeves 9!, that are associated with the feed valves 58, aredirectly connected to portions of the valve housings, and the other twosleeves connect with the boxes 95 which in turn are connected to thehousings of the discharge valves El. Stuffing glands for the stems ofthe .four control valves are omitted to ensure smooth and facile valveactuation, so that fumes from the liquid may escape in limited quantityinto the sleeves 19!. Each sleeve has, at its upper end, a fume sea-ldevice 92 which does not interfere with the valve actuation. Each devicecomprises (see Fig. 12) a liquid-filled cup surrounding and joined tothe upper end of the sleeve, and an inverted cup 53 secured to the rod93 in such manner that its open lower edge is always immersed in theliquid but never in contact with the bottom of the cup 93. If desiredthe sealed vapors within the sleeve may be connected through a conduitit! to the top of one of the feed tanks i3. The reason for including thesleeves 9!, rather than placing the fume seals directly adjacent thecontrol valves, is to elevate the seals so that any abnormal and suddendischarges of inflammable vapor through the seals will be ventedtoatmesphere at points where ignition is extremely unlikely.

In operatiom'each control valve has three stepping positions, viz: (1)full now, (2) dribble flow and (3lcomple elv closed. The dribble flowposition-is'onein which the valve unit 92 is but slightly open, asin 9.Fig. 1c shows a valve fully closed. Figs. 1 and 11 show a valve fullyopened, this position of course being attained when the correspondingcam has the high point of its enlargement disposed the rollerfi i. Whenthe smal er, eubstant my circular portion of the faces its roller 3 5,the corresponding valve riulljv seated .s- .1 ingupon whether the assocated solenoid device (FS or DS) is energized. These solenoid devicesthrough individual follows.

trigger latch mechanisms, as

With reference to Figs. 5, 9 and 10, the free end of each lever 85carries a roller I02 and, just above and to one side of said roller, thelever has a plate I03 secured thereto. These elements are designed forcoaction with a roller I04 carried by one arm of a bell crank I which ismounted on a fixed pivot I06. The plate I03 is adjustable manually byadjustment screws, as shown in Fig. 8, to properly locate said plate toguide the roller I04 for contact with roller I02. The crank has a pinI01 on its other arm slidably received in the slot of a slotted linkI08, the latter being pivotally suspended from the outer end of asolenoid core I09. The elements I02 to I06 form a trigger latch; and theelements I01 to I09 coact with a solenoid coil to form one of thesolenoid devices (FS or DS). Energization and deenergization of the foursolenoids is accomplished individually by movements of the beams of thedual scale system, yet to be de- L scribed, through mercury switches.The switches for the feed solenoids will be designated FSS and those forthe discharge solenoids, DSS.

As shown in Fig. 9, the lever 85 is tending to rise, as permitted by thecam 80, but in so doing its roller I02 and its plate I03 have pocketedthe roller I04 so that the roller I02 can rise no farther. The solenoiddevice is in deenergized condition. The valve 60 is dribbling. Uponenergization of the solenoid device FS through the switch FSS as shownin Fig. 10, the core I09 moves to pull the pin I01 upward by the linkI00, thus swinging the bell crank I05 and releasing its roller I04. Thevalve unit 92 therefore is permitted to seat fully, with lever roller 84riding upon or closely approaching the reduced area of the cam 80. Thelatch and solenoid elements are shown more in detailin other views,described later, and it will then be seen that manual adjustment of theplate I03 toward and from the roller I02 will vary the sensitivity ofthe trigger action. The discharge valve actuating mechanism correspondswith that just described, differing therefrom only in the timing of itscam and switch operation, as brought about through scale operation. Thetwin scale systems are constructed as follows.

Each weigh tank 42 is mounted on a set of weighing levers in which amultiple beam system is incorporated. With particular reference to Fig.5A, each tank 42 is rigidly secured to a pair of vertical members H2 anda similar pair of vertical members H3. Each member H2 is pivotallypinned to an intermediate portion of one of a pair of main scale leversH5, which at one end have fulcrums at II6 on the framework, and which attheir other ends are shackled together and to the lower end of a link II4, as shown. The other members, II3, are pinned at their lower ends tointermediate portions of a pair of levers I I1 that have fixed fulcrumsI I8 at one end. The other ends of levers II1 are shackled to thecenters of the levers H5, as shown. The tank thus is well balanced forvertical movement substantially parallel to the link II I upon which itis, in effect, suspended.

The upper end of the link H4 is pivotally shackled to a short lever I20,one end of which has a fixed fulcrum at I2I and the other end of whichis pivotally supported at I22 on the lower end of a substantiallyvertical and floating bar I23 comprising a pair of parallel rods I24interconnected by three short horizontal cross members I25 (see Fig. 5).The lowermost cross member carries the pivot I22; the intermediate crossmember is engageable at its bottom with a pivot pin I26 carried by oneend of a weigh beam I21; and the uppermost member I25 rides upon a pinI28 carried by one end of a tare beam I30.

Intermediate its ends the weigh beam I21 has a frame-supported fulcrumI31, and likewise the tare beam I30 has a fulcrum I32. The free end ofthe Weigh beam carries a variable weighted pan assembly I33; and thefree end of the tare beam carries a smaller weighted pan assembly I34,likewise variable. The opposite end of the weigh beam also projectsbeyond the pivot I26 to receive a constant weight I35 which, were theweight I33 removed and the pin I26 eliminated, would precisely balancethe beam on its fulcrum pivot.

As a preferred example, the total ratio between the fulcrums H0, H8 andthe link H4 may be 10 to 1; the short lever I20 may have a ratio of 4 to1; and the tare and weigh beams may have a ratio of 5 to l-thus makingthe total ratio of the scale system 200 to 1. As shown in Figs. 1 and 5each pair of scale beams I21, I30 together with electrical mechanismsassociated therewith and yet to be described is disposed within a boxI36, atop which is mounted a smaller box I31 that houses a tolerancemechanism subsequently described as an over-under device.

In the preferred mode of operation each tare beam I30 of the twin scalesis so weighted and mounted that it balances its corresponding weigh tank42 plus a permanent liquid tare or residue. That is, neglectingtemporarily the action of the corresponding weigh beam I21 (and thelatter is actually taken off the system periodically so that its actioncan be thus neglected) the tare beam will be in horizontal balance onits fulcrum when opposed by the mass of a tank 42 containing apredetermined amount of permanent tare. This permanent tare in the caseof a fluid such as gasoline may be pure liquid, and in the case of afluid of high viscosity, such as oil, may be partly liquid and a scum orfilm on the bottom surfaces of the tank. Presence of a permanent liquidtare ensures uniformity of tare for successive weighings.

In further clarification of the above it should be stated that thepermanent tare is augmented for each weighing by adding liquid to thetank 42 through its feed valve 60 until both the weigh beam I21 and thetare beam I30 are in balance, and thereafter discharging the liquidthrough valve BI until a point is reached where only the tare beam isbalanced. Just prior to attainment of this point the weigh beam islifted off the scale system by mechanical means about to be decribed.

As an example, a permanent liquid tare of 1,000 pounds can be attainedby using a mass of 5 pounds in the tare beam weight pan assembly I34(with scale beam ratio 200 to 1), and weighed or measured liquid unitsconsisting of 5,000 pounds each can be attained by using a mass of 25pounds in the weigh beam weight assembly I33. In full balance then, thetank contains 6,000 pounds of liquid, and only 1,000 pounds in emptybalance.

The mechanisms for timing the valves 50, 0I for each scale system andfor lifting its weigh beam into inaction at proper intervals, comprisesthe following parts (see Fig. 5, and Figs. 15-18). The motor drivenshaft 83 is connected to a timing shaft I40 through a pair of gear boxesMI and I42 interconnected by a shaft I39 so that both shafts rotate inunison. Secured to shaft I4!) is a crank arm I43 which, through aconnecting rod I44, actuates a vertically slidable cross-head I45. Thelatter is disposed below the free end of the weigh beam I21 and it risesto engage and lift-or rather prevent downward swinging of said beam-justprior to the time that a full unit of liquid has passed through thevalve 6|. To accomplish this the crank I43 must bear the properrelationship to the cam 8|, and the solenoid device DS must be timedcorrespondingly.

The shaft I49 extends into a recorder I45 to count and record theweighing cycles in obvious manner, and between its ends it is connectedby a chain I41 to a short shaft I48 to drive the latter at the samespeed. This shaft I48 extends into a box I59 within which it carries,for unitary rotation, a set of six timing cams C1, C2, C3, C4, C and Cs,respectively, associated with a corresponding number of individualmercury switches CS1, CS2, CS3, CS4, CS5, and CS6 (Figs. l5-18). Eachswitch has a pivot I5I, and a follower I52 designed to ride upon thecorresponding cam surface to cause periodic openings and closings of theswitch. This group of switches is connected in circuit with the scalemotor SM to cause the latter to run intermittentl under properconditions, as will be more clear upon subsequent discussion of thecircuit diagram of Fig. 34.

igs. 15 to 18 illustrate several positions of the beam lift crank I43and the sets of cam switches CS1 to CS6, relative to each other and theseveral principal scale positions, as follows:

Fig. 15-full flow feed to tank 42 through its valve 63;

Fig. l6-tank 42 full and beams I21, I30 in balance;

Fig. l7-full flow discharge from tank 42 through its valve 6| crank I43about to remove weigh beam from system;

Fig. l8-tank 42 empty except for permanent tare; tare beam I39 inbalance, with weigh beam inoperative due to position of crank I43.

The dribble flow positions of the valves 50 and (ii are directlycontrolled by the solenoid switches, F88 and DSS respectively, throughmovement of the scale beams I21 and I30 respectively, and not by theswitches just described. With reference to Fig. 5, each feed solenoidswitch FSS is mounted in an oscillatable casing I54 that has a fixedpivot at I55 and that normally is in balance with a lever I56 to whichit is connected by a link I 51. The lever has a fixed pivot I58, adepending slotted link I60, and an adjustable balancing weight IGI. Theweigh beam I21 has a pin I52 projecting freely into the slot of link I65so that an appreciable predetermined upward or downward movement of thebeam will cause the link to be picked up and the casing I54 oscillatedcorrespondingly. The switch FSS is so mounted (see Figs. 19-24) as to beopened or closed respectively upon predetermined downward and upwardmovements of the beam I21. Intertied mechanically with switch FSS is adischarge switch DIS which opens and closes simultaneously therewith.

A similar group of switch actuating parts, which may be referred tobriefly as coacting elements I53 to I1I (Fig. 5), is associated with thetare beam I30 and designed to open and close the discharge solenoidswitch DSS upon predetermined movements upwardly and downwardly,respectively, of said beam (Figs. 19-24),

This switch DSS is intertied mechanically with a feed switch FIS whichopens and closes simultaneously therewith.

A somewhat detailed reference to the circuit diagram of Fig. 34 may behelpful at this point. This diagram incorporates electrical devices ofboth sides of a twin scale system, and hence, where duplioate'parts arefound in each side they are distinguished on the diagram by addition ofthe suffixes A and B respectively. For example, the scale motor SM ofFig. 5 is designated SMA on one side, and SME on the other. It should beunderstood that the A and B parts are identical, except for location.The diagram of Fig. 34 is shown for simplicity as a single circuitembodying both the motors and the controlling and signaling devices,whereas in actual practice the several scale and pump motors SMA, SMB,0PM and DPM usually will be disposed in a separate three-phase systemunder control of the branches and devices connected to the two-wiresupply line I12, I13.

A pair of wires I14, I15 is connected to the main line so that thelatter may lead to one side (A) of the dual scale system and the formermay lead to the other side (B). Reading upwardly from the bottom of thediagram, there is but a single discharge pump motor DPM, under controlof the automatic switches DPl and DP2, the latter serving to stop thepump motor when liquid in the tank 4| has receded to a point below whichthe pump would need repriming, and a manually operable residue switchDPR; a single siren OS and a single signal light OL, both operable bythe automatic overflow light switch OLS; and a single overflow pumpmotor OPM, with its signal light OPL, both operable by the automaticswitch OPS and also by the manually operable residue switch ORS. Theremaining parts, with the exception of a time delay coil TDC and a groupof switches TDS, CHD, CHF, FRS and Testwhich are common to the two sidesof the diagram-are duplicated, with one set on the A side and the otheron the B side.

The purpose of the time delay mechanism, comprising the coil TDC and thedouble contactor switch TDS, is to give the scale systems plenty of timeto reach a balance before continued operation of the scale motors ispermitted. Any suitable form of device may be used for this piu'pose, apreferred type being that available on the market under the nameMicroflex and manufactured by the Eagle Signal Corporation of Moline,Illinois, under U. S. Patents Nos. 1,383,533, 1,460,707, and 1,794,762.It is a synchronous motor driven time relay relay with time adjustmentand consisting, basically, of a contact-operating mechanism driven by amotor through an electro-magnetic clutchthe action being automatic,requiring only the closing or opening of a control circuit to initiateor terminate a cycle of operation. This mechanism per se forms no partof the present invention and hence is not fully disclosed in all detail.

The coil TDC is connected in series with a pair of switches labeled OverA and Under A, and with a second pair labeled Over B and Under B, saidswitches forming part of the previously mentioned tolerance deviceswhich ensure weighings within predetermined limits of accuracy. One sideof the switch TDS is connected to the constant head discharge switchCI-ID which in turn is in series with the constant head feed switch CHF.The Test switch is a normally closed manual switch. FRS is a normallyopen feed residue switch that may be manually closed to completely emptythe feed tanks. The other side of the switch TDS has connections,respectively, with the cam switches CSA, CS5B and CSsA, CScB, wherebythe twin scale systems are electrically interlocked.

Manually operable starting switches, ESSA and ESSB are shunted aroundthe time delay and interlocking switches to connect the scale motors SMAand SMB, respectively, directly with the switch CHD, Each motor has aholding coil (HCA or I-ICB) which is operable to close a holdingcontactor (CA or CB) upon closure of one of the starting switches (ESSAor ESSB). The holding contactors are in branch lines with the A and Bgroups respectively of the group of switches FIS, DIS, CS1 and CS3. Asshown, other branch lines include the CS2 and CS4 cam switches, feedpendulum switches FPSA and FPSB and discharge pendulum switches DPSA andDPSB. The manner of automatic actuation of the FPS and DPS switches issubsequently set forth.

The four valve trigger solenoids are differentiated in Fig. 34 bycombining their general reference number IIB with appropriate legends(FSA), (FSB), (DSA) and (DSB).

The lamps BLA and BLB are in series with the respective A and Bover-under switches and hence are lighted to indicate balanced scaleconditions when said switches are closed. Feed lights FL (A and B) arecontrolled by switches FLS (A and B)as by actuating the latter from thefeed valve rodsto indicate that the weigh tanks are being fed. In likemanner, discharge lights DL (A and B) are controlled by switches DLS (Aand B), actuated by the discharge valve rods, to indicate that the weightanks are discharging.

As shown in Fig. 5, and in Figs. 19 to 24, each switch DPS consists ofan encased mercury switch that is secured to one arm of a rigid bellcrank I80. The bell crank has a fixed pivot at I82 and carries a rollerI83 adjacent the switch for coaction with the upper edge of the tarebeam I30. The roller is urged toward the beam by a weight B84 secured tothe other arm of the bell crank. In rising, the tare beam picks up theroller and, in its uppermost position (Fig. 22 full flow dis-charge fromweigh tank) it has oscillated the crank sufiiciently in one direction toopen the switch. In all other beam positions the switch is closed. Astop I85 limits the oscillation of the crank by the weight in theopposite direction.

In a similar manner each member FPS comprises an encased mercury switchcarried by a rigid bell crank I86 that has a fixed pivot I81, the crankarms carrying a roller I 88 and a weight I89 respectively. A stop I90limits oscillation of the crank under influence of the weight in onedirection. Oscillation in the other direction is eifected by the weighbeam I2'I which, in swinging downwardly, engages the roller I88. Theswitch is open only when the beam is in or immediately adjacent itslowermost position (Fig. l9full flow feed to empty Weigh tank).

It may be helpful to the reader at this point to describe briefly theconditions of the scale system corresponding to the beam and switchpositions illustrated in Figs. 19 to 24:

Fig. 19weigh tank 42 empty and feed valve fully open; switch FPS open,and cam switches CS1 to CS6 as in Fig.

Fig. 20-weigh tank nearly filled and feed valve in dribble position ofFig. 9;

Fig. 21-weigh tank full with beams in balance; switch FSS just closed topermit feed valve to close fully; cam switches disposed as in Fig. 16;

Fig. 22-weigh tank discharging with discharge valve fully open; switchDPS open; cam switches as in Fig. 17; weigh beam I2'I lifted 01f scalesystem by crank I43 to separate the elements I25, I25;

Fig, 23weigh tank nearly empty with discharge valve dribbling; weighbeam still off th scale system; and

Fig. 24-weigh tank empty except for permanent tare; tare beam balanced;weigh beam about to be permitted to return to operative position; camswitches as in Fig. 18.

The driving arrangements and valve operating mechanism of Figs. 6 to 8are essentially no different from the showing of the same in Fig. 5, butFigs. 6 to 8 illustrate the actual details of a commercial embodiment.Instead of driving the cam shaft 83 directly from the speed reducer 82as in Fig. 5, a chain HM and appropriate sprocket wheels are utilized tointerconnect shaft 83 and a short shaft I92 that projects from the speedreducer. The shaft 83 is fully supported on the frame by a plurality ofspaced bearings I93. The apparatus of Figs, 5-8 is duplicated for atwinscale system having sides A and B, as aforementioned.

Operation The operation and cooperation of the apparatus and electricaldevices thus far described is as follows, beginning with an assumedcondition that all tanks are entirely empty.

Before pumping liquid to the feed tanks 43, both feed valves must beclosed, so that each is ready to open and feed to its respective weightank 42. The scale beams at this time are disposed as in Fig. 19, withall three switches connected to the weigh beam broken but with all threeswitches connected to the tare beam in contact. Referring to Fig. 18,the switch CS1 is closed. The scale will not operate under theseconditions until: (a) the level of liquid in the feed tanks reaches apredetermined height to close the constant head feed switch CHF; (12)there is enough room in the receiving tanks 4|, as determined by theconstant head discharge device CHD, for the discharged weighings. Whensuch conditions exist, as shown by suitable indicators, and theTestfswitch is closed, the empty starting switch ESSA for the A side ofthe system may be manually pressed, whereupon the motor SMA starts andthe holding coil HCA will be energized to close the switch CA. When theswitch ESSA opens upon release of manual pressure, the motornevertheless continues to run because of the circuit established throughswitches CA, FISA and CSiA; The latter switch breaks, however, afterapproximately /4 revolution of that cam shaft 83 which is driven by themotor SMA; and any suitable braking means,electrical or mechanicalmay beprovided to ensure quick and accurate stopping of shaft rotation whenthe motor is deenergized.

By the above operation the feed valve 69 of the A side is placed infully open position by one of the cam enlargements 96, and thecorresponding weigh tank is being filled rapidly. After about 85% (notincluding tare) of a predetermined load of liquid is within this tankthe corresponding weigh and tare beams come to the dribble positionunder the influence of the feed pendulum weight I83 (see Fig. 20), butbefore this weight comes to rest on its stop I98 the mercury switch FPSAmakes contact. It should be noted here that before the motor SMA stoppedon its initial movement (before CSiA broke), switch CSzA made contact(Fig. 15); and that when FPSA now makes contact it completes a circuitwhich starts the motor and turns the cam shaft 33 another A; revolution(until CS2A breaks) to place the feed valve in dribble position (Fig.9). Before CSzA breaks, however, CSsA and 085A are made (Fig. 16) forthe next part of the weighing cycle.

As soon as the remaining 15% of liquid enters the weigh tank, the beamsI27 and I39 come up to full balance (Fig. 21), and, in doing so, causethe switches FSSA and DISA to make contact. FSSA thereby energizes thesolenoid H8 (FSA), which then trips the trigger rollers I02, I04 andpermits the feed valve to close fully, as in Fig. 10.

The operator now presses the empty starting switch ESSB to start the Bside of the systemthe scale motor SMB and other parts going through thephases above described for the A side, so that the other weigh tank isloaded. The scale system is now primed and will operate automatically aslong as there is a sufiicient supply of liquid. Status of system at thispoint:

1. Both wei 2i tanks carry full balanced weighings.

2. Sides A and B not yet properly synchronized.

3. Beams as in Fig. 21.

4. Cam switches as in Fig. 16.

. Over-under switches A and B closed by attaininent of balance, asexplained later.

Upon attainment of the above conditions a circuit is produced throughthe over-under switches A, the timer coil TDC and the over-underswitches B. The timer has been set previously to operate with apredetermined time delay, upon the expiration of which the doublecontactor switch TDS is snapped to the closed position illustrated inFig. 3e; and as the CS5 switches are already closed while the CS6switches are open the only possible motor operating circuit is throughthe A side. However, immediately that the motor SMA starts, thecontactor CA is closed to ensure continued operation through a circuitincluding the closed switches CSsA and DISA. CSsA breaks afterrevolution of the cam shaft, and during this movement the dischargevalve 6| on the A side was moved to fully open position. Breaking ofCSsA stops the motor because the initial circuit through the CS5switches and TDS is also now open (see Fig. 17). Just prior to breakingof CSsA, switch CSiA was closed.

Heretofore no mention has been made of the movement of the beam liftcrank M3 and its actuatcd crosshead M35 as the latter has done no work.It has sim ly followed the weigh beam (Figs. 1921) without touching itexcept in Fig. 19 where it served as a stop for the beam on full flowfeeding. But now it does some work in that it lifts the weigh beam (sideA) to free it from the system and thus impose the whole load on the tarebeam I35 during the weighing out or discharge of liquid into thereceiving tanks 4| (Figs. 22 and 23).

The discharge valve is fully open, and after approximately 85% (notincluding the permanent tare) of the liquid is discharged from the weightank, the tare beam comes to its dribble position (Fig. 23) under theinfluence of the discharge pendulum weight E84. Before thelatter engagesits stop I85, the switch DPSA makes contact, establishing a circuit byway of CSA to the motor SMA and its coil HCA. Switch CS4A breaks afterthe motor has turned the cam shaft another revolution, and the motorthen stops because- FISA and CSaA being brokenthe contactor CA is unableto establish an independent circuit for the motor. The discharge valvenow is in dribble position, held there by the roller trigger. Justbefore CSiA breaks, switches CS1A and CSsA make contact for the nextoperation. When the remaining 15% of the liquid (not including tare) isdischarged from the weigh tank, the tare beam 39 comes to balance (Fig.24) and in doing so it causes switches DSSA and FISA to make contact.This actuation of the discharge solenoid switch (DSSA) causes thesolenoid H6 (DSA) to trip the trigger and fully close the dischargevalve 6! of the A side.

Status of scale at this point:

1. Sides A and B of the scale system properly synchronized, the twoWeigh tanks of the sides being in empty balance and full balance,respectively.

2. Scale beams of side A as in Fig. 2 those of side B as in Fig. 21.

3. Cam switches of side A as in Fig. 18; those of side B as in Fig. 16.

Now that the scale is synchronized, each side is 180 degrees out ofphase with the other. With CSsB and CSA in contact and if switches CHDand CHF are in contact, any closure of the double contact switch TDS nowwill make a circuit not only through the A side of the scale as in theprevious operation but also through the B side, thus keeping the systemin correct synchronism during further operation-that is, causing thesides to alternate on feeding and discharge, with the weigh tank of onebeing fed while the other weigh tank is discharging. Repeated cycles areas above outlined, with the CS5 and CS6 switches serving to maintain thesynchronism. 'The timer TDC is energized only when the over and underswitches are closed on both sides of the system, thus making continuedoperation impossible if the scale should weigh for any reason outside apredetermined guaranteed accuracy. Upon correcting the error by bringingthe scale to balance or by pressing both of the empty starting switches,ESSA and ESSB, the scale will again go into automatic operation.

From the foregoing, it will be seen that the cam switches give a timingor sequence efiect to the controls preparatory to closing the variouscircuits to the motor, and the beam controlled switches FSS, DIS andDSS, FIS complete the circuits as the weighing action is partiallycompleted and again when completed. It will be noted from Fig. 34 thatthe cam switches CS5 and CS6 are in duplicate and designated CSsA, CSaBand CSeA and C363, those with the suffix A being operated by the A sideof the system and those with the suffix B being operated by the B sideof the system. By following the circuits, it will be seen that switchesCSsA and CS5B operate to energize motor SMA only and that switches CSGAand CSGB operate to energize the motor SMB only. The mechanical relationof the switches CS5A and CScA to the valve cams and Bi on the A side ofthe system is the same as the mechanical relation of th switches CSsBand C363 to the corresponding valve cams on the B side of the system.If, by some manipulation, switches CSsA and CSsB were both closed,switches CSeA and G363 would be open. Complete closing of both motorCircuits would then be impossible since, starting at line I12 andproceeding through coil I-ICA to switch CSsA, a circuit paralleltherewith will be closed through the closed switch CSsB, and energywould be supplied to motor SMA. Starting with the line I'M andproceeding through coil HCB to switch CSeB, this switch and also switchCSeA would be open so that motor SMB would not be' energized. SwitchesCSsA, CSsB and CSsA and (3363 thus serve to assist in properlyinterlocking the twin system electrically.

When it is desired to make a test weighing, the normally closed Testswitch is opened. If this is done during the process of a weighing thescale will not be interrupted, but after it has finished that particularWeighing it will pause as long as the Test switch is open, holding afull balance in one tank and an empty balance in the other. Fullautomatic operation will be resumed upon closure of the Test switch.

If at any time during a run the liquid is pumped from its source to thefeed tanks faster than the weigh tanks can take it away, the feed tankswill overflow into the overflow tank 44. If a certain level is reachedin the latter, float switch OPS makes contact and starts the motor PM,at the same time lighting the red lamp OPL. If the overflow continues sorapidly as to raise the level considerably higher, float switch OLScloses and sounds the siren OS, while also lighting the danger signallamp OL.

If at the end of a run it is desired to empty the system and the head ofliquid in the feed tanks 43 is below the level required to maintain.switch CHF closed, the overflow residue switch OBS is made, startingthe overflow pump motor 0PM for the purpose of returning any liquid inthe overflow tank M to the feed tanks. If no overflow occurred, or thereis insuflicient overflow liquid to close CHF, the feed residue switchFRS is manually closed. Thereupon, if the level in the receiving tanksis low enough to close CHD, the scale will operate until it hascompletely emptied the feed tanks.

Over-under devices Each side of the scale has associated therewith oneof the boxes I3? (Fig. 5) containing the tolerance mechanism thatactuates one of the pairs of over and under switches (Fig. 34), all aspreviously explained in a general way. One of these mechanisms now isdescribed in detail, with particular reference to Figs. to 33.

A spindle I95, journaled in the box I'3'I in any suitable manner,carries a plurality of parts some of which are free to rotateindependently of the spindle and others of which are secured thereto.The secured parts include a collar I95 united to a plate I91 thatcarries the over and under switches, shown structurally in Fig. 25 asmercury switches I98 and I99 respectively. A pair of horizontal arms200, 202 form rigidly aligned extensions of the collar I95arm 20Dcarrying a pivotally suspended link 293, and arm 292 carrying a mass 204that is adjusted to serve as a counterweight for the link. The lower endof link 223 has a vertical slot 205, so disposed when the arms 200, 202are in horizontal balance that the center of the slot is disposed tosurround a pin 2G6 whenever the tare beam I3ilto which the pin issecured-is in perfect balance. (The weigh beam [21 could carry the pin,but as said beam is sometimes off the scale system, it is preferred toutilize the tare beam for this purpose.)

Should'the tare beam, when weighing liquid, fail to come to balance atthe proper time within a weighing tolerance determined by the length ofthe slot 285 and the angles of inclination of the mercury switches I98,I99 with respect to their plate I91, one or the other end of the slotwill be in engagement with the pin and will have shifted the lattervertically in one direction or the other to open one of the switches. Apointer 28?, secured to the front end of the spindle, 00- operates witha scale 208 to show whether the unit volume of liquid is overweight orunderweight, and the extent of the error. Normally, of course, theweighings will be accurate within the prescribed tolerance. In the eventof occasional error, however, any one of the four switches (ove1"A andB, and under-A and B) will prevent continued operation of the system, aspreviously explained with reference to Fig. 34.

The complete over-under mechanism is more than an indicator and switchoperator. It includes, between the collar I and the pointer 26?, meansacting as compensation on the beam system and steadying the tare beam.This means includes a pair of dash pots Zlll filled with a special oiland secured to the bottom of the box I31 at opposite sides of thespindle I95. These dash pots do not act upon the beam system at alltimes, for if they did, the beam movement would always be retarded,which would be undesirable because the tare beam must swing quickly andfreely from its dribble positions (Figs. 20 and 23) to the balancedposition in order for the weighings to be correct.

Each dash pot receives the lower end of a rod 2 I2, to which it isfluid-coupled by a disc 2I3 that normally rests upon a nut or integralenlargement 2I4 of the rod. The disc fits the rod very loosely, as shown(Fig. 28), and has a clearance of about inch with respect to the innercylindrical wall of the dash pot. Therefore, the dash pot is singleacting, imposing resistance to rod movement upwardly but permitting therod to move freely and rapidly in a downward direction in advance of itsdisc. The latter, of course, sinks to follow the enlargement 2 I4.

The upper end of each rod is pivotally connected to an arm 2I5 that issecurely joined to a collar 2I6 that has an internal bearing 2I'I bywhich it is anti-frictionally mounted for oscillation on the spindleI95. Each collar 2I6 rigidly carries a second arm, 2I8, in alignmentwith arm 2I5 and provided with an adjustable counterweight 2I9; and athird substantially vertical arm 220 carrying a pendulum mass 222 thattends to maintain the aligned arms 2I5, 218 in horizontalism. The lowerend of each arm 22B is engageable with an adjustable stop pin 223.

The parts just described will occupy the position illustrated in Figs.25 and 26 unless oscillated to other positions by an operating member224 that is secured to the spindle I95. This member has two actuatingfingers 225, arranged so that in one direction of spindle rotation onlyone collar 2I6 is oscillated and that in the other direction only theother collar is oscillated. The fingers carry adjustable pins 226 whichare engageable with the arms 220 to cause the oscillation justmentioned.

Assuming that one of the weigh tanks is full and its corresponding scalebeams balanced as in Fig. 21, the over-under device will occupy thebalanced position shown in Figs. 25 and 26. Upon discharging the liquid,the tare beam will go to the position of Fig. 22 and the over-underdevice

